A zoo in the German city of Nuremberg said it killed 12 baboons on Tuesday despite protests, capping a saga rooted in concerns that the zoo had too little space to house a growing group of the animals.

Twelve baboons were shot dead at a German zoo because there was not enough space in their enclosure. Tiergarten Nürnberg zoo has sparked outcry from animal rights groups after culling the healthy animals and feeding them to predators. Animal rights groups fear that apes and monkeys could be culled in the UK as zoos struggle with overpopulation.

Zoo director Dag Encke defended the decision to cull the baboons in a news conference, saying that the decision had been a “yearslong consideration” and that by doing so, they helped to maintain a healthy baboon population at the zoo, in line with the the European Association of Zoos and Aquaria (EAZA)’s policies.